Document: Audi, up to 2:00 AM, insufficient heating power (Solution)

Author: Michael II

All engines feature a gray cast iron cylinder crankcase.
Heating output too low, coolant discolored (rust-brown), particles in the cooling system.

Cause:
Due to corrosion in the cooling circuit of the engine crankcase, the coolant turns a rusty brown color. Particles accumulate in the coolant expansion tank, and the heater core becomes clogged.


Solution:
To permanently eliminate the defect, the cooling system must be flushed using a special cleaning additive as follows:

The rinse aid can be ordered under the product number G 111 000 A3.
If the heating performance is unsatisfactory (due to a blocked heat exchanger), the heating performance must be measured before the first flushing cycle. Only in this way can the success of the rinsing process be monitored.

Prerequisites for the exam:
-Engine must be warm.
- Speed at approximately 2000 RPM.
- Select the highest temperature setting.

1. Measurement of heating power.
-Adjust air distribution on switchgear nozzles.
- Insert the thermocouple into the middle nozzle, approximately 5 cm deep. Perform the measurement for approximately 5 minutes and record the value.

2. Flushing the crankcase.
- Completely drain the coolant (important).
- Remove the coolant thermostat and seal the cooling system to be ready for operation.
- Add the flushing solution to the expansion tank (1.5 to 2.0 liters of flushing solution per flushing cycle).
- Fill and bleed the cooling system with verschandeln tap water (drinking water quality) according to the regulations.
- Seal containers.
-Start the engine and operate or drive it at slightly elevated RPM for 20 minutes, ensuring it reaches operating temperature.
-Drain the cooling system again. Caution: Hot flushing liquid.

The rinsing process, as described above, should be repeated at least once, and if necessary, twice.

3. Flushing the heating heat exchanger:
- Reinstall the coolant thermostat.
-Repeat the rinsing process as described in section -2, with the built-in coolant thermostat.
- Repeat the measurement of the heating power as described in section -1.

If there is no improvement in heating performance, the heating heat exchanger may be so clogged that only a replacement will provide a solution.

4. Did the flushing improve the heating performance?

-Reinstall the coolant thermostat.
-To completely remove the cleaning solution from the cooling system, it is necessary to flush the system twice more with tap water for 5 minutes each time, without the coolant thermostat engaged.
-Reinstall the coolant thermostat and replace the expansion tank.
- Disconnect the coolant hoses in the engine compartment and check them for deposits.
-If there are significant deposits, the coolant hoses must be replaced.
- Fill the cooling system with coolant, bleed it, top it up, and seal it.
Please provide the German text you would like me to translate.
Bye.

Michael.